Just replaced my laptop screen, screen is black?

Well my laptop screen broke about 3 months ago and I've been using an external monitor ever since. Just now, I finally got a replacement screen for my laptop. Anyways, Initially when I was using the external monitor, the screen on the laptop would be glowing as well. Then after a while I believe it stopped. When I replaced my laptop screen (I followed the procedure correctly from a video on youtube), the new screen was black even though the laptop was on and functioning. I then connected it back to my external monitor and it was still working fine. I then took the screen a part again, made sure I connected the video cable properly and tried it again. Didn't work. I tried taking out the battery and power cable out, holding down the power button for a minute, and turning it back on 3 times. Didn't work. I then took out my ram cards, left them out for a while, then but them back in (changing their slots) and it still didn't work. I then tried to start up the machine with only one ram card in, nothing. I then ran a windows memory diagnostic to see if there was any problem with the ram, and it reported no problems whatsoever. I then went and installed the latest display drivers for my graphics chipset, still no luck.

I'm really out of options here and have no idea what's causing the problem. There is no inverter since it's an LED screen. I also put a flashlight on it and there is no image on the screen when the laptop is turned on. My best guess is that there's something faulty with the connection from the display to the laptop (whether it's the cable or some connector) since the computer doesn't detect any built in display.

I'm stumped. Suggestions are much appreciated.

The model is an HP Pavilion G6 with an AMD A6 3400M APU.